Hypodermic syringe



Jan. 17, 1950 A. E. SMITH HYPODERMIC SYRINGE Filed July 1, 1946 in/l,

INVENTOR.

ARTHUR E. 5/7/ TH BY mama Patented Jan. 17, 1950 UNITED (STATES PATENTOFFICE HYPQDERMIC SYR'I'NGE Arthur E. Smith, Los Angeles, Calif.

Application July 1, 1946, Serial No. 680,748

'2 Claims.

The present invention relates to improvements in hypodermic syringes andhas particular reference to the type of syringe in which a cartridge,comm-only termed an ampule, is insertable, and which includes adetachable tubular needle.

The general object of the invention is to pro vide an eflicient syringefor administering 'penioillin-oil-wax and other hypodermic medicinalcompound or solution. A further object is to provide a simple syringewhich is so inexpensive that ampules, containing the sterilizedmedicinal compound or solution, and the needle thereof may be quicklyinserted and discarded after each injection.

Another object of the invention is to provide improved means forcentering the ampule within the casing of the device and to :guide itproperly during the injection operation. A still further object is toprovide an improved ampule structure :fitted with specially designedclosures at the ends thereof for iacili-tating loading of the ampule andeviction of the medicinal solutions therefrom.

Another object of the invention is to provide means for retracting theplunger cork to determine whether cr not the needle point has entered ablood vessel prior to injecting the medicinal compound.

These and other objects of the invention and the many advantages thereofwill be apparent from the following detailed description and .byreferring to the accompanying drawings, of which:

Fig. l is a side view of a completely assembled syringe embodying theinvention;

Fig. 2 is a substantially corresponding view of the syringe as itappears before the ampule is mounted therein, and with parts incross-section for the sake of clearness;

Fig. 3 .is a sectional side view of the ampule as it appears beforeinsertion into the syringe;

Fig. i is a substantially corresponding end view of the ampule;

Fig. 5 is a cross-sectional view of one of the parts thereof; and

Fig. 6 is a side view of the hypodermic needle used in the syringe.

The syringe consists of two main portions namely, a casing I, withinwhich a plunger 2 is axially fitted to slide. casing is closed by ascrew cap 3, and the cylindrical body portion of the casing istransversely perforated to provide openings or windows I I forconvenience in assembling and operating the syringe.

The outer end of the The plunger 2 is tubular and is fitted at one endwith internal screw threads 2 of a size to receive the threaded end i ofa tubular cap 1 within which a tubular needle 6 is rigidly secured. Theplunger is also made with a hand grip 5 which, for convenience, in thedrawings takes the shape of a circular, flaring head, but it may "bemade in any other shape. When the needle is mounted in position withinthe plunger it is noticed that the inner end 6* thereof projects a shortdistance beyond the inner end of the plunger. The latter is in Fig. 1,for the sake of clearness, shown in an intermediate position, but it isto be understood that as a preliminary to seating of the ampule withinthe casing I, it is necessary to withdraw the plunger until the shoulder2 thereof comes to a stop against the shoulder i of the casing,whereupon the cap 3 is unscrewed.

The ampule, in the preferred form illustrated in the drawings, comprisesa transparent tube ill which is closed at one end by means of a cap ill,and a small piston H is seatable for axial sliding movement therein. Theampule is designed to hold any predetermined amount of medicinalcompound or solution and, as this may vary with the kind of solutionused and with the dosage required, it is merely necessary before theclosure ll is seated to insert the piston into the end of the tube andto advance it within the tube until the space between the piston and theclosure II is of a volume to correspond to the amount of medicinalsolution desired. Closure .H is next inserted into the end of the ampuleand the space between H and l2 is filled with the medicinal compound bya needle through diaphragm 1 l Ampules, as above described, arespecially de-- signed for loading and delivery by the pharmaceuticalmanufacturer :so as to be ready for immediate insertion in the syringeand, as above stated, are discarded .upon completion of the injection.

It is now noticed that the piston I2 is internally threaded, as shown inFigure 5, or fitted, as shown in Figure 4, with a metal insert l3 whichis internally threaded for engagement with a threaded projection 2 atthe inner end of the plunger. Once the ampule has been seated inposition within the syringe and the cap 3 mounted thereon to maintainthe ampule confined therein, the syringe is ready for use. It is thenmerely required to advance the plunger into the casing until theshoulder portion 2* enters the ampule tube l0 and the threaded end 2 ofthe plunger reaches the threaded opening l3 of the piston I2, whereuponthe plunger is rotated in order to screw this end in position within thepiston. The latter is preferably made from suitable soft material suchas rubber and, as indicated in Fig. 5, is made with a thin centrallylocated membrane l2 through which the inner end of the needle penetrateswhen the plunger is screwed into position therein, thereby to open apassage for the solution within the ampule to the interior of theneedle.

It is quite necessary that the piston be tightly fitted within theampule, and it is also important that it is so designed that it may beaxially slidable therein without exerting undue pressure on the plunger,and it is for this reason shown made with a series of annular grooves l2The closure H is also preferably made from soft rubber or otherresilient material, and it is noticed that the inner end thereof isrecessed at I l to form a substantially hemispherical seat for the endof the piston. When so constructed it is seen that the closure may bemade long enough to insure against leakage or accidental dislodgementand that because the end of the piston seats therein all of the contentsof the ampule may be expelled and no part of the contents thereof needto be wasted.

In inserting the needle into the patient it occasionally happens thatthe needle enters a blood vessel. This is an occurrence which thepractitioner is always guarding against, and it is of considerableimportance to him to be able to determine whether or not such puncturehas occurred. It is one of the great advantages of the present inventionthat this may be readily determined after the needle has been insertedin the patient by merely withdrawing the plunger within the casing avery short distance. In doing this, it is noticed that the piston I2 ismoved correspondingly within the ampule thereby to create a partialvacuum therein, a vacuum which causes blood, if present, to be drawnthrough the needle into the ampule and so to enable the practitioner todetermine by a mere glance at the syringe Whether or not a blood vesselhas been penetrated.

Another great advantage of this device is that the plunger is alwaysperfectly guided axially within the casing, particularly because theshoulder portion 2 thereof enters and fits into the end of the ampulebefore the screw threads reach and engage the threads l3 of the piston,thereby to make sure that the needle and the end of the plungercorrectly engage the piston and that during the injection operation theplunger and piston are continuously axially guided within the ampule soas not to impart any side strain thereto.

It is also important to note that the outer end of the plunger isinternally threaded, and that for this reason the threads thereof areprotected against accidental damage in handling the syringe, and alsoagainst dirt and other foreign matter. Still another advantage of thisarrangement is that the needle can only be inserted in one direction,and that for this reason the inner, pointed end 6 thereof always assumesthe proper position beyond the end of the plunger.

From the foregoing description it will be apparent that I have provideda very simple and eificient syringe combination which is convenient toassemble and use.

I claim:

1. In a hypodermic syringe, the combination .with a cylindrical casingand a needle holder axially slidable therein, said needle holder havingexternal screw threads at the inner end thereof and a needle extendabletherethrough, of a cylindrical ampule seated within the casing, a pistonof resilient material snugly fitted to slide within said ampule, aninternally threaded tubular insert axially seated within said piston,the piston having annular grooves in the periphery thereof and beingmade with a substantially semispherical projection rising from the innerface thereof, a resilient shouldered stopper forclosing the other end ofthe ampule, said stopper having a recess sunk into the inner surfacethereof of a size to receive the projection of said piston, there beinga thin membrane between the bottom of said recess and the outer surfaceof the stopper.

2. For use in a hypodermic syringe, a cylindrical transparent ampuleopen at both ends, a resilient piston seatable for sliding movementwithin said ampule and having a spherical projection at the inner endthereof, an internally threaded recess portion within said piston at theopposite end thereof, said inner end portion of the piston beingrecessed to form between the outer surface of said inner end and thebottom of said threaded recess portion a thin membrane, a resilientshouldered stopper for the opposite end of the ampule, said stopperhaving a recess in the inner surface thereof of a size to receive thespherical projection of the piston and a small recess extendingtherefrom to form between the bottom of the recess and the outer surfaceof the stopper a thin membrane.

ARTHUR E. SMITH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,817,003 Hein Aug. 4, 19311,833,598 Smith Nov. 24, 1931 1,848,711 Hall 1. Mar. 8, 1932 1,909,591Nevin May 16, 1933 2,176,042 Pittenger Oct. 10, 1939 2,229,739Harrington Jan. 28, 1941 2,377,274 Smith May 29, 1945

